Metal Flake-Surfaced Roofing Materials

ABSTRACT

The present invention relates to roofing materials for roofs, sidewalls and other exterior surfaces exposed to the weather such as, but not limited to, asphaltic and non-asphaltic roofing materials, wherein metal flakes cover up to 100% of the weathering surface of the roofing materials. The metal flakes may be applied to the surface in striations or bands separated by conventional roofing granules or may be blended with conventional roofing granules. The metal flakes may have antimicrobial potential and may provide resistance to microbial growth to roofing materials when dispersed in or applied thereto. The present invention also relates to methods of making the roofing materials.

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/210,501, filed on Aug. 1, 2002, which is a continuation ofU.S. patent application Ser. No. 09/590,222, filed on Jun. 8, 2000, nowabandoned.

FIELD OF THE INVENTION

The present invention relates to metal flake-surfaced roofing materialswhich may be used for roofs and also for sidewalls and other exteriorsurfaces exposed to the weather. The roofing materials which may besurfaced with metal flakes include, but are not limited to, asphalticroofing materials and non-asphaltic roofing materials such as concrete,plastic, rubber or metal roofing materials that have other materials onthe exposed surface to provide a weathering surface or which are usedfor aesthetic purposes. The present invention further relates to methodsof making the metal flake-surfaced roofing materials. Metal flakes maybe applied to the surface of roofing materials as the sole surfacingmaterial or in combination with typical colored roofing granules. Anyroofing material that uses colored roofing granules, crushed naturalstone, or coatings on the exposed roofing surface can have metal flakesapplied thereto, in place of or in addition to the roofing granules,crushed natural stone, or coatings, in accordance with the presentinvention.

BACKGROUND OF THE INVENTION

Roofing materials, such as roofing shingles, are made from a widevariety of materials, including metal, slate, concrete, plastic,asphalt, etc. Asphalt roofing materials have the advantages of goodperformance in extreme temperatures and areas where wind, water and iceare of concern. In addition, asphalt roofing materials offer enhancedefficiency in that they can be produced in high volume and can be easilyinstalled, resulting in lower costs and improved overall value.Furthermore, asphalt roofs require little upkeep and are easily repairedwhen damaged. However, many asphalt roofing materials do not have thesame aesthetic qualities as metal and slate roofs and most do not havethe equivalent life span. Moreover, asphalt shingles, as well as certainnon-asphaltic shingles, such as concrete shingles and plastic shingles,are prone to microbial growth staining.

To address the problem of microbial growth staining, non-metal roofingmaterial manufacturers have offered several types of microbial resistantproducts, many of which incorporate antimicrobial agents such as metalions to inhibit microbial growth staining.

For instance, antimicrobial agents have been mixed with the granuleswhich surface certain asphaltic roofing materials. U.S. Pat. No.5,573,810 and U.S. Pat. No. 5,356,664 describe copper containing algaeresistant roofing granules which may be applied to the surface of anasphalt roofing material together with non-algae resistant granules.U.S. Pat. No. 4,092,441 describes metal algaecides which are sprayed inthe form of droplets of molten metal onto the surface of roofinggranules. The metal, which may be zinc, copper and/or other metalalgaecides, inhibits microbial growth.

In addition, U.S. Pat. No. 5,599,586 describes the application ofantimicrobial agents in the form of a polymer film, with improvedweatherability, to the surface of roofing materials. Similarly, U.S.Pat. No. 3,932,143 discloses flame-spraying a first layer of metal on atleast one side of a shingle and flame-spraying a second layer of copperon the first layer.

U.S. patent application Ser. No. 09/590,222 also discloses a surfacecovering building material including a component having antimicrobialpotential to resist microbial growth-induced staining of the material.The component having antimicrobial potential consists essentially of (a)a copper component selected from the group consisting of copper powderand copper flakes and (b) a barium metaborate monohydrate component.

U.S. Pat. No. 2,133,988 describes a method of increasing shingledurability by using very fine aluminum flakes on the shingle surfacebetween the larger mineral surfacing rock to block ultravioletdegradation of the asphalt coating and to lower the temperature of theshingle, thereby promoting asphalt stability and preventing blistering.U.S. Pat. No. 2,332,219 describes mixing the aluminum flakes with othermaterials to reduce dust, increase asphalt compatibility for reflowingthe aluminum to the surface, and aid in adhering the aluminum flakes.The aluminum flakes may be used as the sole shingle covering or may beblended with mineral surfacing. The aluminum flakes may be adhered toother mineral rock granules and aluminum dross may be used as a granuleor surface granule in whole or in part. The size of the flakes rangesbetween 150 and 350 mesh.

U.S. Pat. No. 4,617,198 discloses a metal chip application equipment forlow slope applications. A water bath is used to cool a modified capsheet and the chips are projected or flung onto the sheet. Chipmaterials include aluminum, magnesium and tin. The chips are rectangularchips having a size ranging from 10 to 200 mils on a side, preferably 60to 80 mils on a side, by 1 to 2 mils thick. The patent also disclosesthat chips having a larger size than 200 mils on a side are not suitabledue to their inability to withstand wind gusts when the cap sheet havingthe metal chips is applied on a roof.

Metal and slate roofing materials generally do not have the problem ofmicrobial growth staining. The advantages of metal roofs are that theyare aesthetically pleasing, durable, long lasting, lightweight,ecologically sound, fire retardant, and energy efficient. Thedisadvantages of metal roofs are that they are expensive, requireinstallation by a professional trained in metal roofing installation,and can be damaged or dented by outdoor elements, such as hail. Tegola(Pasiano, Italy) manufactures a copper foil shingle which is an asphaltstrip shingle that has a copper foil over the exposed portion of theshingle. The copper foil-asphalt strip shingle is easier to install thanconventional metal shingles.

Slate roofs have the advantages of long life, fire resistance, highstrength, low maintenance, and an aesthetically distinctive appearance.Slate roofs, however, are heavy and expensive. Further, slate exists inlimited color choices, requires frequent maintenance, can be easilydamaged (particularly during maintenance due to walking on the roof),and relies on underlayment which usually fails before the slate.

Accordingly, there exists a need for a roofing material with improveddurability and aesthetic qualities. There is also a need for a roofingmaterial which has an appearance of a metal or slate shingle but whichdoes not have the expense, manufacturing, weight, leakage or maintenanceproblems associated with such shingles, and which is easily installed.

SUMMARY OF THE INVENTION

The present invention is a metal flake-surfaced roofing materialcomprising a headlap and a weathering surface, wherein the weatheringsurface comprises metal flakes and the headlap is substantially free ofmetal flakes, wherein the metal flakes cover greater than 0.001% and upto 100% of the weathering surface. Roofing materials that may besurfaced with metal flakes in accordance with the invention include, butare not limited to, asphaltic roofing materials, non-asphaltic roofingmaterials (such as concrete, rubber and plastic materials) and otherexterior cladding building materials. The metal flake-surfaced roofingmaterials of the present invention provide the advantages of metalshingles and the water proofing and easy installation of asphaltshingles. In addition, metal flake-surfaced roofing shingles have animproved appearance and durability. Further, the metal flake-surfacedroofing materials of the present invention may exhibit resistance tomicrobial growth-induced staining thereon. Moreover, the flakes may bemade using recycled metal, so that the use of metal flakes to cover anasphaltic shingle with the flakes is cheaper than conventional metalsheet roofing. Furthermore, the metal flake-surfaced roofing materialsare less expensive on an installed basis than conventional metalshingles, such as copper shingles or tin shingles, and can bemanufactured by the same production process as used, for example, forasphaltic shingles. In particular, labor costs for the installation ofthe roofing materials of the present invention are up to three timeslower than the costs required for the installation of metal or slateshingles.

The roofing materials of the present invention, whether asphaltic ornon-asphaltic, include flakes of metal dispersed on the surface of theroofing material.

In one embodiment of the invention, where the roofing material is anasphaltic composite, such as an asphalt roofing shingle, the metalflakes are dispersed on the surface of the shingle intended for weatherexposure, or “weathering surface,” so as to cover the entire area ornearly the entire area of that surface. In another embodiment of thepresent invention, the metal flakes are applied to the weatheringsurface of the shingle, or a portion thereof such as the backer strip ofa laminated shingle, in bands or striations which are separated byregions whereon standard roofing granules have been applied. In afurther embodiment of the present invention, the metal flakes areapplied to the weathering surface of the shingle such that the surfaceof the shingle is covered by approximately equal amounts of metal flakesand standard roofing granules.

The present invention also provides a method of making the metalflake-surfaced roofing material comprising heating the metal flakesprior to or after application of the flakes to the roofing material.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood with reference to theattached drawings in which—

FIG. 1 shows an exemplary embodiment of a metal flake-surfaced roofingshingle according to the present invention, where nearly the entireweathering surface of the shingle has been covered with metal flakes.

DETAILED DESCRIPTION

This invention is not limited to any particular roofing material and maycomprise surfacing a wide variety of such materials with metal flakes,including asphaltic and non-asphaltic roofing materials. Representativeexamples of such roofing materials include, inter alia, those roofingmaterials described in U.S. Pat. Nos. 3,886,021; 4,082,885; 4,405,680;4,468,430; 5,305,569; 5,565,239; 5,666,776 and 5,743,985 which areincorporated herein by reference. The roofing materials may be invarious forms including, for example, asphalt roofing shingles,non-asphaltic roofing shingles, roofing tiles, roll roofing, commercialcap sheets, modified bitumen cap sheets, shakes and sidewalls.

As used herein, the term “weathering surface” does not include theheadlap of the roofing shingle. Accordingly, the metal flakes areapplied so as to cover the entire area or nearly the entire area of theweathering surface, while the headlap of the roofing shingle remainssubstantially free of metal flakes.

The metal flakes may be applied to the roofing materials by any methodknown in the art. For example the metal flakes may be applied in asimilar manner as roofing granules are applied to an asphaltic roofingshingle, i.e. the metal flakes may be applied to an asphaltic shingleduring the asphalt shingle making process while the asphalt is stillhot. In addition, the metal flakes may be heated and then applied to asurface of an asphaltic roofing material in order to adhere the metalflakes to the surface of the roofing material. Alternatively, the metalflakes may be applied to the surface of a roofing material and thenheated to ensure that the metal flakes are adhered to the surface of theroofing material. The metal flakes are preferably applied to theweathering surface so that the metal flakes do not substantially overlapwhen the roofing material of the present invention is applied to a roof.

Stone coated metal shingles use an acrylic coating to adhere coloredroofing granules to the metal. This process may be used in accordancewith the present invention to apply metal flakes to any roofingmaterial. For example, copper flakes may be applied to a steel shingleby such a process. The application of copper flakes to a thin steelshingle may result in a shingle that is thinner and lighter thanconventional copper shingles but still retains the desiredcharacteristics of conventional copper shingles.

Flex Shake™ (US Century, California) is a roofing product made from usedtires (recycled steel reinforced rubber). An adhesive coating is appliedto the surface of the rubber for the application of slate chips orcolored roofing granules. In accordance with the present invention,metal flakes may be correspondingly applied to the surface of the rubberusing an adhesive coating.

The metal flakes may be of any metal. Nonlimiting examples includecopper, tin, zinc, aluminum, brass, bronze, steel, stainless steel,lead, or any other desired metal. The metal flakes may be made fromrecycled metal to lower the cost of the roofing material. Moreover, themetal flakes may be coated, preferably with ceramic paints, to achieveany desired aesthetic appearance, such as an appearance of any metal orstone. The metal flakes need not contain barium metaborate monohydrate.

The metal flakes may be interspersed with conventional roofing granules(e.g. colored roofing granules) to provide unique aesthetic appearances.For example, the interspersement of metal flakes and roofing granulesmay produce the appearance of bands or striations to achieve aestheticcharacteristics, such as to enhance the ability of the resultant shingleto provide a perception of depth to the roof.

In another embodiment of the present invention, asphaltic roofingmaterials are covered with metal flakes and standard roofing granules inapproximately equal amounts. The flakes dispersed on the shingle mayprovide resistance to microbial growth by remaining present during theweathering of the material. For example, where the roofing material ofthe present invention is an asphaltic composite, such as an asphaltroofing shingle, copper flakes may be added to and dispersed throughoutthe filled asphalt portion of the building material to produce a shingleresistant to microbial growth staining. In addition, copper flakes maybe added to any portion of the roofing materials of the presentinvention, including the entire material to produce a shingle resistantto microbial growth staining. Any metal capable of inhibiting microbialgrowth may be used to produce a shingle resistant to microbial growthstaining, as herein indicated.

As used herein, resistance to microbial growth-induced staining refersto resistance to such staining during the weathering of the roofingmaterial for the normal life of the material (i.e. from about one tofifty years).

The filled portion of the roofing material, as used herein, refers toany portion of a roofing material including a filler material known inthe art including, inter alia, filler materials described in U.S. Pat.No. 5,965,257; U.S. Pat. No. 5,391,417 and U.S. Pat. No. 4,405,680,which are incorporated herein by reference.

In addition, the roofing material of the present invention may benon-asphaltic, such as, but not limited to, cement tile and compositeimitation slate, and is surfaced with metal flakes to produce the metalflake-surfaced roofing materials of the present invention.Alternatively, the non-asphaltic roofing material may include metalflakes having antimicrobial potential dispersed throughout any portion,including the entirety, of the nonasphaltic building material.

The roofing material may be a bitumen cap sheet and the metal flakes maybe applied onto the bitumen cap by laying the flakes flat on the sheet.

The metal flakes may have antimicrobial potential, i.e. they are capableof conferring resistance to microbial growth. Any suitable metal flakeshaving antimicrobial potential capable of withstanding the processingtemperatures involved in making the asphaltic or non-asphaltic roofingmaterials may be employed in accordance with the present invention. In apreferred embodiment, the antimicrobial metal flake is copper flake.More than one type of metal flake may be used in accordance with thepresent invention. For example, copper flakes and tin flakes may be usedto achieve a particular aesthetic or antimicrobial effect.

The metal flakes having antimicrobial potential preferably inhibit thegrowth of cyanobacterium, which is a microbe often responsible formicrobial fouling of roofing materials. The metal flakes preferablywithstand high heat, mixing and abrasion without significantly losingtheir antimicrobial properties.

The metal flake-surfaced roofing materials of the present inventionprovide a durable and aesthetically pleasing roofing material and havean improved life compared to conventional roofing materials. In apreferred embodiment, the metal flake-surfaced roofing materials have alife of greater than 40 years when used on a roof. In a particularlypreferred embodiment, they have a life of greater than 50 years whenused on a roof. Additionally, roofs covered with the metal flakematerials of the present invention demonstrate greater light (solar)reflectivity (i.e., the energy repulsion of a “cool roof”) and enhancedhail impact resistance. Thus, utilization of the materials of thepresent invention affords many of the benefits of slate roofs withoutthe added weight and cost and complexity of installation. Metal flakesmay be less than half the thickness of the same metal used inconventional metal shingles. For example, copper shingles can measure0.025″ in thickness and metal flakes can average 0.007″ in thickness.

The metal flake-surfaced roofing materials can have an appearance, forexample, of a metal roof (such as a copper roof), or a slate roof. Whentin flakes are employed, the roof may have an appearance of a tin roof.In a preferred embodiment, the roofing material of the present inventionis a copper flake-surfaced roofing material. When the copper flakesoxidize from exposure to the elements, they turn various colors. Ascopper ages from its original bright shine it goes through brown orbronze tones and then ultimately to its renowned green patina. When thecopper flake-surfaced roofing material of the present invention achievesthe green patina, the roofing material may resemble a slate roof. Thecoverage of an asphalt roofing material with metal flakes according tothe present invention can produce a roofing material with the benefitsof both asphaltic roofing materials and metal roofing materials. Theresultant roofing material (asphalt shingle surfaced with metal flakes,such as copper flakes) is durable, aesthetically pleasing, relativelyinexpensive, easy to install, low maintenance, long lasting and may befurther resistant to microbial growth staining. Coating of the metalflakes, for example with ceramic paints, may achieve any desiredaesthetic appearance.

Additionally, the metal flake-surfaced roofing materials of the presentinvention may provide architectural qualities, e.g. a roof surfaced withthem does not look flat but rather has a three-dimensional architecturallook. Furthermore, architectural qualities are imparted to the metalflake-surfaced roofing materials by applying the metal flakes instriations or bands which are separated by conventional roofinggranules, such as ceramic roofing granules, or by blending the metalflakes with roofing granules. The interspersement and/or blending of themetal flakes and roofing granules allow the roofing materials of thepresent invention to impart to a roof a more three-dimensionalappearance. In addition, different metal flakes (e.g., tin andcopper/steel and bronze) may be blended together to achieve uniqueaesthetic appearances and may also be blended with roofing granules.

In a preferred embodiment, the metal flake-surfaced roofing material ofthe present invention comprises from about 20 lbs. to about 70 lbs. ofmetal flakes per 100 square feet of roofing material. In a particularlypreferred embodiment, the metal flake surfaced roofing material of thepresent invention comprises from about 45 lbs. to about 65 lbs. copperflakes having a thickness of about 0.07″ to about 0.018″ per 100 squarefeet of asphalt shingle. In another preferred embodiment, the metalflake-surfaced roofing shingle of the present invention comprises fromabout 25 lbs. to about 50 lbs. copper flakes having a thickness of about0.006″ to about 0.011″ per 100 square feet of asphalt shingle. Inanother embodiment, the metal flake-surfaced roofing shingle of thepresent invention comprises aluminum flakes having a thickness of atleast about 0.012″. The thickness of the metal flakes is such that themetal flakes do not ignite when subjected to UL 790 or ASTME-108 Class Afire testing. Accordingly, the amount of metal flakes per 100 squarefeet of roofing material may vary considerably and depends on the metaldensity, metal thickness, size distribution and desired aestheticappearance. The metal flakes are preferably greater than flakes having asize passing through a U.S. Standard Sieve #50. For example, the metalflakes can range in size from passing through a U.S. Standard Sieve #50up to 1″ in size. The metal flakes may be obtained from FisherScientific, of Pittsburgh, Pa. The thickness may range from about 0.001″to about 0.0125″. In one embodiment, the thickness of copper flakes maybe from about 0.007″ to about 0.012″. The sieve analysis for copperflakes having an average thickness of 0.0079″±0.0010″ (using U.S.Standard Sieve) is shown in Table I below:

TABLE 1 Sieve Copper Flake +8 11.8% +12 20.5% +16 48.1% +20 18.3% −20<1.3%

The roofing materials of the present invention have advance UL 790 orASTME-108 Class A fire classifications for asphalt fiberglass shingles.Other shingles that have weathering surfaces comprising metal flakesretain their fire ratings. A preferred method for making the metalflake-surfaced roofing materials of the present invention comprisesadding the metal flakes to the roofing material during the roofingmaterial making process, wherein the metal flakes are affixed to thesurface of the roofing material. For example, the metal flakes may beapplied to an asphaltic roofing material while the roofing material isstill hot and not yet solidified, whereby the metal flakes are affixedto a surface of the asphaltic roofing material. In another embodiment,hot metal flakes are applied to the surface of a roofing material,whether asphaltic or non-asphaltic, such that the metal flakes areaffixed to the roofing material. Alternatively, the metal flakes may beapplied to the surface and heated after application to the surface, suchthat the metal flakes are affixed to the roofing material.

In one embodiment of the present invention, the metal flakes are ofsimilar size to conventional roofing granules. In such an embodiment,the process of applying the metal flakes to a roofing material may besimilar to the process of applying conventional roofing granules to aroofing material. In contrast, known metal roofing processes involvesheet or coil metal and the shingles are formed by stamping, bending orpunching which is cumbersome. In addition, known metal roofing processesrequire special shingle cutting equipment.

When the metal flakes are to be included in a filled portion of amaterial, the metal flakes may be dispersed throughout the filledportion during the roofing material making process. The metal flakes sodispersed may provide resistance to microbial growth by remainingpresent during the weathering of the roofing material. The metal flakeshaving antimicrobial potential that are added to the filled portionduring the roofing material manufacturing process must retain theirantimicrobial potential during the heat of processing of the materialwhich ranges from about 50° C. to about 500° C. The metal flakesincluded in a filled portion of the material are preferably smaller thanthe metal flakes covering the weathering surface, ranging in sizebetween mesh size 40 and mesh size 200.

The invention is further illustrated by reference to the followingexamples.

EXAMPLES Example 1 Preparation of Copper Flake-Surfaced AsphalticRoofing Material

A line trial was conducted in which 5½ bundles of shingles were madewith full copper flake coverage. The copper was applied to asphaltshingles according to methods known in the art for applying roofinggranules to asphalt shingles during the asphalt shingle making process.The copper flake coverage, loading and adhesion to the asphalt shingleswas very good. Table II below summarizes the data for a copperflake-surfaced shingle made in accordance with the invention:

TABLE II Regular Colored Granite Shingles Trial Copper Shingles RunAverage Run Average (pounds) (pounds) Difference Square weight 279 316+37 Top Coating 53.3 83.5 +30.2 Rubloss 0.24 0.35 Butt Granule 28.2 65.2+37

The shingles described in Table II were laminated shingles like thoseillustrated in U.S. Pat. No. Des. 369,421 having a backstrip with blackcolored granules. The exposed portion of the top layer of the shingleswas entirely covered with copper flakes. The copper flakes were in theform of platelets supplied by OMG Americas, Research Triangle Park, N.C.The thickness of the copper flakes ranged from about 0.001″ to about0.0125″.

The square weight increase appeared to be completely due to the copper.While the top coating showed only a 30 pound increase in the loading ascompared to the 37 pound increase in the square weight, this wasprobably due to copper flakes spreading to the headlap in significantamounts.

Although the present invention has been described in detail withreference to specific exemplary embodiments thereof, variousmodifications, alterations and adaptations may be made by those skilledin the art without departing from the spirit and scope of the invention.It is intended that the invention be limited only by the appendedclaims.

1. An asphaltic roofing material comprising a headlap and a weatheringsurface, wherein the weathering surface comprises metal flakes and theheadlap is substantially free of metal flakes, wherein the metal flakescover substantially the entire weathering surface of the roofingmaterial, wherein the metal flakes are coated with a coloring agent, andwherein the metal flakes have an uncoated thickness of about 0.001inches to about 0.0125 inches.
 2. (canceled)
 3. (canceled)
 4. (canceled)5. The roofing material of claim 1, wherein the metal flakes areselected from the group consisting of copper flakes, tin flakes, zincflakes, aluminum flakes, steel flakes, stainless steel flakes, bronzeflakes, brass flakes and combinations thereof.
 6. (canceled)
 7. Theroofing material of claim 1, wherein the metal flakes have antimicrobialpotential.
 8. The roofing material of claim 1, wherein the roofingmaterial comprises a filled portion, and wherein the filled portionincludes metal flakes.
 9. The roofing material of claim 1, wherein theroofing material is made by a process comprising applying the metalflakes to the weathering surface of the roofing material.
 10. Theroofing material of claim 1, wherein the metal flakes are first heatedand then applied to the weathering surface.
 11. The roofing material ofclaim 1, wherein the metal flakes are first applied to the weatheringsurface and then heated.
 12. The roofing material of claim 1 wherein theroofing material is made by a process comprising dispersing the metalflakes throughout a portion of the roofing material.
 13. The roofingmaterial of claim 12 wherein the portion is a filled portion.
 14. Theroofing material of claim 1, wherein the metal flakes are dispersedthroughout the material and are applied to the weathering surface of thematerial during the material making process.
 15. The roofing material ofclaim 1 wherein the metal flakes are dispersed throughout a portion ofthe material and applied to the weathering surface of the materialduring the material making process.
 16. The roofing material of claim 1wherein the roofing material is an asphaltic roofing material.
 17. Theroofing material of claim 1, wherein the metal flakes are of a sizegreater than the size of flakes passing through a U.S. Standard Sieve#50.
 18. The roofing material of claim 17, wherein the metal flakesrange from a size greater than the size of flakes passing through a U.S.Standard Sieve #50 to 1″.
 19. An asphaltic roofing material comprising aheadlap and a weathering surface, wherein the weathering surfacecomprises metal flakes and the headlap is substantially free of metalflakes, wherein the weathering surface of the shingle is covered byapproximately equal amounts of metal flakes and roofing granules,wherein the metal flakes are coated with a coloring agent, and whereinthe metal flakes have an uncoated thickness of about 0.001 inches toabout 0.0125 inches.
 20. An asphaltic roofing material comprising aheadlap and a weathering surface, wherein the weathering surfacecomprises metal flakes and the headlap is substantially free of metalflakes, wherein more than half of the weathering surface of the shingleis covered by metal flakes, wherein the metal flakes are coated with acoloring agent, and wherein the metal flakes have an uncoated thicknessof about 0.001 inches to about 0.0125 inches.